A utility scale photovoltaic plant contains tens to hundreds of independently operating inverters that convert photovoltaic-generated DC energy into AC for feeding the electric grid. Until now, the inverters provide the local control for power factor and/or voltage regulation and the plants lack a centralized control system that is capable of providing dynamic voltage or power factor regulation at the plants point of common coupling or point of intersection to the electric grid.
As the utility scale plants continue to increase both in size and population, simple inverter level voltage and power factor regulation is no longer sufficient. More sophisticated photovoltaic plant control systems are needed that provide centralized voltage and power factor regulation.
In addition, the utility scale plants are not always populated with same-type or same-operating characteristic inverters, generally all from a single manufacturer, the systems must be capable to operate with different equipment supplied by different manufacturers.
Also, the control systems must be capable of lowering the real power output of the plant if required to accommodate effective and reliable electric grid operation.